rohman



H.- D. ROHMAN.

CAR LIGHTING SYSTEM.

APPLICATION man m. 20. 1911 1,306,079. I I PatentedJune 10, 1919.

I g 9 MM a'muuu 15/6 6' c {I l 5 1 l llnlggn lmmm a 17' /7 QA ITEI) STATE-S PATENT OFFICE.

HARRY D. ROI-IMAN, OF NEW YORK, N. Y., ASSIGNOIt, BY MESNE ASSIGNMENTS, TO 3'. STONE & COMPANY, LIMITED, OF DEPTIEORD, ENGLAND.

CAR-LIGHTING SYSTEM.

Specification of Letters Patent. Patented June 10, 1919.

.. Application filed February 20, 1917. Serial No. 149,759.

To all whom it may concern:

Be it known that I, HARRY D. RoHMAN, a citizenv of the Republic of Switzerland, residing at New York city, in the county of New York and State of New York, have invented certain new and useful Improvements in Car-Lighting Systems, of which the following is a specification. v

This invention relates to improvements in electric lighting and heating systems such as are used for railway and other Vehicles and it has for one of its primary objects the provision of a simple but effective arrangement for maintaining constant voltage in the consuming or translatin circuits regardlem of how many groups of lamps or other translating devices are in use. Another of the primary objects of the invention resides in the provision of such an improved arrangement whereby itis possible to obtain the desired resultswith the use of standard commercial, parts, such as can be readily purchased in the market, in place of special apparatus ordinarily employed. v

The foregoing, together with such other objects as may hereinafter appear, or are incident to my invention, I obtain by means of a construction and arrangement, the preferred embodiment of which I have shown in the accompanying drawing in diagrammatic form.

'Referring to the drawing, A indicates a" dynamo for supplying the consuming circuit and also charging the storage battery B, the latter being preferably a two-unit battery. The dynamo A may be of any type, but I prefer-to use a dynamo of the speed controlled type, such as a slipping belt dynamo in which the belt, when the train reaches the critical speed at which the dynamo delivers;

full output, say for example 15 miles per hour, begins to slip, the armature thereafter rotating at approximately the same rate of speed regardless of variations in train speed.

The main positive lead is indicated by the that of the battery, and which opens when the dynamo voltage drops below that of the battery in order to prevent reverse fiow of current from the battery. D, E, F-andH indlcate translating or consuming circuits,

the translating devices in this instance being the lamps.

The two-unit battery is provided with the usual change over switch 9, such switch beunit is on charge the other is connected to the consuming circuits so as to float thereon, the particular unit making up any deficiency in the dynamo supply, as is well understood in this art.

It is an essential in present day standards of train lighting equipment that the lamp voltage shall remain substantially constant,-

that is to say, that any flickering of the lamps shall be avoided, either when the dynamo cuts in and replaces the battery in supplying the consuming circuit, or when the cut-in switch opens and the battery alone supplies the consuming circuit, and this irrespective, of whether one, two, or three or more groups of lamps or, translating devices are in use or are cut-in or cut-out. I propose to obtain this result by means of a novel and improved arrangement of the system, substantially as follows:

'The wires 10 and 11 are respectively the positive and negative mains of the consuming circuit D, and for the purpose of this specification, I shall designate this circuit as the main consuming circuit. The positive lead 10 of this circuitis connected to the positive main 7 through the medium of resistance a; and thenegative lead 11 is connected to the negative main 8. G represents the main lamp switch and is adapted to complete the consuming circuit D when it is closed, and when it is open it is adapted to connect the units ofthe battery B in parallel Y through the medium of the wire 12 and 'eX- I tension 13 on one of the blades of the switch so that when the lamps are not lighted the units of the battery will be charged in parallel by the dynamo.

When the switch is closed the circuit,

D may be supplied from the dynamo througlr. resistance a, Wire 10, wire 11 and back to the dynamo through negative 8. It may also be supplied when the train is standing or is traveling below the critical speed by one unit of the battery through wire 14 and by the other unit of the battery through brush 15 carried on the cut-in switch C, contact 16, and'wire 17 which is connected to, positive lead 10. By this arrangement, the resistance a is in eflect short main through resistance Z) and is adapted to be connected at its other end to positive lead 100i circuit D through the blade 18 of a two-pole single throw switch 6. The nega tive return" 19 of circuit E is adapted to be connected to the negativellead ll of circuit D bythe blade 20 ofswitch e and wire 20.

The positive lead 21 of circuit F is connected topositive main :7 through resistance a, andis adapted to be connected to positive lead 10 0f circuit D through the blade 22 ofa double pole single throw switch f.

The, negative lead 23 of circuit Fv is adapted V tobe connected to thenegative 11 of circuit D throughtheblade 24 of switch f and wire 25. Y 7 7 It will be noted that the connections of the positive and negative leads of the circuits E and F respectively to the positive and negative leads of the circuit D are at a point beyond themain switchG and thepon: nection of wire 17 towire 10, l

The operation is as follows in order to light any of the circuits D, E, and vF, the

'main switch G is closed, such main switch also servingas a switch for circuit DQHAS- suming that the swltchese and f are open and the switch G is closed, thecircuit D will 7 be supplied by thedynamo A, or the battery B in the manner already described." It

nowit is desired tolight the lamps in circuit E, switch ,e is closed; Assuming that,

the dynamo is supplyingthe consuming circuits, the current is supplied from the dynamo to circuit D through resistance a as previously noted, but a portion of the current also passesthrough resistance 6 to the The positive lead 17 of circuit, E is connected at one end to the positive lamps of circuit E returning via wire 19, blade 20 and wire 20 to the negative 11 of circuit D and thence to the negative main 8.

The resistances a and b are placed in pan allel by the closing of switch 6, and the resistance is therefore reduced in proportion to the increased lamp load, so that when switch a is closed, there is no flickering on the lamps and the voltage is maintained substantially constant. Assuming now that the train stops or is traveling below the critical speed, the unit of the battery 'B will supply the circuits D and E. Circuit D will be supplied by one unit through wire 14, and by the other unit through wire 7, brush 15, contact 16 and wire 17 as above noted. The lamps of circuit E, also, will be supplied by both batteries via wire 10, blade 180i switch 6, wire 17 to the lamps, current returning via wire19, blade 20, wire207, negative lead 11 to the battery.

Now assuming that the dynamo is again supplying the lamps and it is desired to light the lampsof circuit F in addition to circuits and E, switch f is closed and the dynamo supplies circuits D and E in the manner hereinabove described. A portion of the current, however, from the dynamo also passesthrough resistances wire 21 to v the lamps of circuit F returning viawire 23,

blade 24, wire 25, negative lead 11 to the negative main 8. When the switch f is closed the resistance 0 is placed in parallel with resistances a and b and the total resistance s decreased in proport on to the n; creased load so that there is no fllcker ng on the lamps and the voltage is. maintained substantially constant. Assumingnowthat V the train is at rest or isxtraveling below critical speed, theunits of the battery will supply the circuits D and E inthemanner already described and the lamps of circuit willalso be supplied from wirelO, through blade 22 of switch fiwire 21,to the lamps,;

current returning via wire 23, blade 24:,wire V 25 andrnegativelead ll to thebattery,

It will beseen from the foregoing that, the

switches a and 7' close the respective circuits E and F by establishing the return lead; place the respective resistances b and c in parallelvvith resistance a by connecting the. respective positivel'? or'21 of the circuits E and F with the positive 10 of circuit D1; and

at the same time provide arpathfor battery j a E. MQF. to the circuits E and 'F around the resistances a, b, and so, such resistances being in eifect short circuited as hereinbefore noted. 7

It will also beseenthat when the dynamo 1s supply ng the lamps through thevarious resistancesor any of them, a portion of'the current goesto charge the part cular unit of battery B on charge while thelotherf unit is I directly connected to the positivelead 10. It will of course be understood that when the batteries are'ochanged over, theunit formerly'on chargewill be directly connected to the positive 10 while the unit formerly on discharge will be charged by that portion of the current of the dynamo diverted by the resistance orresistances. Since the unit on charge will have a higher voltage than the other unit, and since the two units of the battery are placed in parallel when the cutin switch C opens, it will be apparent that provision must be made to maintain the lamp voltage at the proper point when the batteries are thus supplying the lamps in parallel. This is accomplished by placing a small resistance 17 in the wire 17, the resistance having a value such as will take care of the relatively higher voltage of the particular battery unit on charge. By this arrange ment in combination with the change-over switch, it will be seen that when the automatic switch C opens, the particular unit of the battery on which the lamps fioat will supply current directly to the positive lead 10 through wire 17, while the other unit which has been on charge will supply current to the positive lead 10 through wire 17 and resistance 17 It will be seen from the foregoing therefore that I have provided a very simple system whereby it is possible to supply two or more circuits either from the dynamo or from the battery as the case may be and at the same time the lamp voltage is maintained substantially constant regardless of whether one or more circuits are in use, regardless of whether the dynamo or the battery is supplying such circuit or circuits, and regardless of the change over from the dynamo to the battery and vice versa from the battery to the dynamo which occurs When the train stops or travels above or below the critical speed. It will also be seen that one main lamp switch serves to break the circuit for all groups of lamps. The arrangement is such that I am enabled to use, with the possible eXce tion of the extension 13 on the main switch standard-commercial switches which can be purchased in the market. I am thus enabled to eliminate any special or com plicated mechanism and at the same time am enabled to secure the desired results. This application is directed to the broad subject matter contained in this and my copending application, Serial Number 149,758, filed February 20, 1917.

I have found my improved arrangement to be very valuable in cars having a great many circuits such for example as a diner and which usually has about ten circuits. In such service, however, these circuits are only used alternately so that one resistance a, b, or 0, will serve for a number of these groups of alternately used lamps. I accomplish this by connecting two or more of the groups of lamps in parallel to illustrate which I have shown such one additional groups of lamps H the positive lead 26 of which is connected'to the positive lead 21 of circuit F. The negative 27 of circuit H is adapted .to be connected to the. negative 11 by a two-pole single throw switch h in the manner already described, such switch also serving to connect the positive lead 26 to the positive 10. Since the groups of lamps F and H are only used alternately, resistance 0 will serve for both groups of lamps in maintaining proper lamp voltage. It will of course be understood that other groups of lamps may be similarly connected in parallel. For dining car service, I have found that the groups may be connected so that the three resistances a, b, and 0 will suffice to take care of all of the groups. Thus this portion of the equipment is standard for both ordinary and special car service conditions.

I claim:

1. In a car lighting system, the combination of a dynamo, a battery to be charged, a plurality of translating circuits in circuit with the dynamo and the battery, a resistance element for each translating circuit, and circuit closing means adapted to connect the positive leads of the translating circuits to place resistances in parallel and to connect negative leads of translating circuits and to provide a path for battery E. M. F. around said resistances.

2. In a car lighting system, the combination of a dynamo, a battery to be charged, a plurality of translating circuits, in circuit with the dynamo and the battery, a resistance element for each translating circuit, a two-pole single throw switch for each translating circuit adapted to connect positive leads of said circuits thereby connecting re sistances in parallel with respect to dynamo E. M. F. and to connect negative leads of said translating circuits thereby providing a path around said resistance for battery E. M. F.

3. In a car lighting system, the combination of a dynamo, a charging circuit, a battery in said charging circuit, a plurality of translating circuits, the positive lead of each'of which is connected to the positive main of the charging circuit, and the negative returns of which are connected to the negative main of said charging circuit, a resistance in the positive lead of each translating circuit and circuit closing means for each circuit adapted to connect the positive lead of the respective circuit with the positive lead of another circuit and to connect the negative lead of the respective circuit to the common return.

4. In a car lighting system, the combination of a dynamo, a charging circuit, a battery in said charging circuit, a main translating circuit in circuitwith said charging circuit, a resistance in said main translating circuit, a switch controlling said main:

translating circuit, a second translating circuit, the positive lead of Which is connected to the positive lead of the charging circuit and the negative return of Which is adapted to be connected to the negative return of said main translating circuit, a resistance inv HQD. ROHMAN.

Copies of this patent maybe obtained for five cents each by addressing the vcommisisionerr of Patents, Washington, D.= C. 

